One of the key criticisms of the ethical review process is the time taken to decision, and associated resource use. A key source of delay is that most submissions are required to respond to at least one request for further information or clarification from the Human Research Ethics Committee (HREC). This study audited the request letters of a single Australian public health HREC using content analysis. Twenty-four submissions were analysed, including 355 individual request elements. Most submissions received a single request letter. There was a mean number of 14.2 (SD = 5.5) elements per letter for the first request and a mean of 2.1 (SD = 1.2) for subsequent requests. Administrative errors were the most common source of request for further information, occurring in all submissions. The second most common theme was the content of the Participant Information and Consent Form, occurring in 79% of submissions. Other common themes, present in over 50% of submissions, concerned: data collection and study procedures; general ethical considerations; recruitment and consent; site, setting or patient pool; research design and methodology; and data management and security. In terms of the general purpose of the HREC comments, 44% were direct corrections or specific requests for changes, 42% were asking for more information or clarification of existing information, and 14% were the HREC expressing concerns about an element of the study, without directly suggesting a change. Overall, the study provides some evidence to show that the quality of the submission (ensuring correct attachments, up to date documents, clear information etc.) could account for a significant proportion of the burden and delay associated with ethical review.